Gasoline pump calculator

ABSTRACT

A calculator for use in a gasoline dispenser or the like for calculating amount of sale and volume dispensed, and for displaying the amount and volume of sale and the price per gallon. A pulse generator actuated by the flow meter provides volume pulses at a relatively low rate as a function of volume dispensed. Volume pulses are counted directly for volume computation. Each volume pulse gates on a clock pulse generator running at a relatively high rate, with the on time controlled by a preset price counter. Clock pulses are counted for amount of sale computation and are counted for gate on time control.

United States Patent o PULSES/GAL.

Burke et al. 51 May 30, 1972 [54] GASOLINE CALCULATOR 3,549,868 12 1970Watson et al. ..235 92 FL [72] Inventors: William F. Burke, Westminster;Daniel A.

Gihring, Orange; Thomas E. Jones, Costa axamlfer Maynard w'lbur Mesa allof Calm Assistant ExammerJoseph M. Thesz, Jr.

Attorney-l-lar1is, Kiech, Russell & Kern [73] Assignee: Pan-Nova, Inc.,Santa Fe Springs, Calif. 22 Filed: Apr. 30, 1971 [57] ABSTRACT [2!]App]. No; 138,912 A calculator for use in a gasoline dispenser or thelike for calculating amount of sale and volume d1spensed, and fordplaying the amount and volume of sale and the price per gal- [52] US.Cl ..235/92 FL, 235/94 A, 235/l5l.34, Ion A pulse generator actuated bythe fl meter providgs 235/92 235/92 PE volume pulses at a relatively lowrate as a function of volume [51] Int. Cl dispensed volume-pulsesarecounted directly for volume [58] Field of 'gff g gfij computation. Eachvolume pulse gates on a clock pulse generator running at a relativelyhigh rate, with the on time controlled by a preset price counter. Clockpulses are counted [56] References Cited for amount of sale computationand are counted for gate on UNITED STATES PATENTS controls- 3,043,5087/1962 Wright ..235/92 FL 9 Claims, 1 Drawing Figure VOL UME ACCUMULATOR,4'/* E 0 016/771 a/spmv m .l: 23- 0 2 GALLONS CLOC'K jmhz 33 {M2 g SALEACCUMULATOR GEM GA E 0 0 g 33 u 0 D v 23 Q5 2/ RESET 6/ 34 7 66 I wPR/CE COUNTER RESET A;CCUMULATO%5 40 D 4/ D D gggg'- Lilli 2513?? 4 42 T54 0 36 u-r 53 LOG/C 52 g cg zo 43 05c. 0.5a. 45

DECODER 0 5 5 y v w ipaa /zli 7 49 44 SELECTORQ BACKGROUND OF THEINVENTION This invention relates to calculators for material dispensingand in particular to a new and improved electronic calculator for usewith dispensers, such as gasoline and other fuel dispensing devices. Theinvention will be described herein as applied to a gasoline pump such asis utilized at the modern day service station. A typical gasolinedispenser includes a fluid pump, a pump control switch, a hose withnozzle for insertion into the vehicle tank, a flow control on thenozzle, and one or more manually controlled levers which function tostart and stop the pump and reset the calculator. Fluid flow through thenozzle is measured, the volume of material dispensed is calculated anddisplayed, the cost or monetary amount of the sale of the material iscalculated and displayed, and the price, e.g., cents per gallon, isdisplayed. Some arrangement is provided for changing the price.

Mechanical calculators have been in use for a considerable period oftime in gasoline dispensers. Electronic calculators have been proposedand several are shown in existing patents. The patent to Wright, U.S.Pat. No. 3,043,508 shows an electronic. multiplier for fluid dispensershaving a flow meter which generates pulses as a function of fluid flow,and provides forsampling the pulses periodically with the sampling timebeing preset as a function of price, with the sampling occurring in aprice sealer having a first set point corresponding to the price and asecond set point corresponding to the sampling rate. The flow rate pulsegenerator operates at a relatively high rate for this type of device, inthe order of 4,000 pulses per gallon. An oscillator provides an inputfor the price scaler, with the oscillator operating at a relatively lowfrequency in the order of khz, whichis about one order of magnitudegreater than the flow meter pulse rate for present day gasoline pumpingrates.

The patent to Livsay US. Pat. No. 3,081,031 shows another electroniccalculating apparatus with the flow meter providing an output at about1,000 pulses per gallon, with this pulse outputbeing counted directly toprovide an indication of volume. Decimal counting is utilized andcertain count states of the volume counter are selected as a function ofprice, to provide the amount of sale figure.

Giot et al. US. Pat. No. 3,221,149 discloses-another electronic meteringand computing apparatus in which the pulses from the flow and in whicheach pulse provides a full cycle of operation of another thirteen stagecounter with the counter cycle shutting off at the 13th count and withthe counter being tapped at various count states to provide inputs to anamount of sale counting unit. The th 1 1th and 12th counts are used ascontrols for permitting advance pulses from a lower decade to a higherdecade so that these advance pulses cannot occur simultaneously with theinputs from the first nine counts of the 13 stage counter.

SUMMARY OF THE INVENTION The calculator of the invention includes apulse generator producing electrical pulses at a relatively low rate asa function of material dispensed, and a clock generator which producespulses ata relatively high rate. The clock output is gated on by eachpulse from the pulse generator and is gated off by a price counter whichis manually set to the price of the material being dispensed. The clockoutput is transmitted to a sale accumulator and to the price counter,with the on time being controlled by the number of clock pulses requiredto advance the price counter to the preset price. The sale accumulatorcounts the clock pulses and provides an output reading in the amount ofsale. The pulse generator output may be counted directly in a volumeaccumulator to provide an output reading in volume. The price countersetting provides an output of price and all three outputs may besuitably displayed. Circuitry is provided for rounding off the amount ofsale at the half-cent and circuitry is provided for resetting the systemwhen the transaction is completed or when a transaction is initiated.

It is an object of the invention to provide a new and improvedelectronic calculator for gasoline dispensers and the like. It is aparticular object of the invention to provide such a calculator whichcan operate with a flow meter having a low r.p.m. and a low pulse rate,permitting a low inertia system with minimal start and stop problems. Afurther object is to provide such a system having low rotational error,with the error being independent of the amount of sale. Additional ob,-jects include provision of manual setting which may be' applicable to aplurality of dispensing units and displays, halfcent round-ofi, andcontinuous indication and agreement between volume dispensed and amountof sale.

DESCRIPTION OF THE DRAWING The drawing is a diagrammatic illustrationprimarily in block diagram form showing a presently preferred embodimentof the calculator of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT A flow meter, such as aconventional positive displacement meter, is mounted in the pipeline l0upstream of the dispensing nozzle. A pulse generator provides electricalpulses as a function of flow and typically may comprise a reed switch 11actuated by one or more magnets 12 carried on a rotating shaft 13 drivenby the meter. Each closure of the switch 11 connects a voltage source 14to the input of a driver amplifier 15. The pulse generator preferablyoperates at a relatively low rate, typically pulses per gallon which maycorrespond to four meter revolutions per gallon with a 25 to 1 step upin the pulse generator, generators of this type being commerciallyavailable today. Present day gasoline pumps deliver fuel at a rate inthe order of 10 to 15 gallons perminute, with a corresponding pulsegenerator output in the order of 25 pulses per second. Withthe pulsegenerator providing 100 pulses per gallon, a unit volume of materialdispensed would be one one hundredths of a gallon. v

The pulse generator output pulses are referred to herein as the volumepulses, with the number of volume pulses being a direct function of thevolume of material dispensed. The volume pulses are connectedas theinput to a volume accumulator comprising four counter decades Dconnected in series. These may be conventional binary coded digitalcounters, with the output of each decade driving one element of the fourelement volume display 20. Nixie tubes or other conventional numeraldisplay elements may be utilized.

A clock generator provides clock pulses at a relatively high rate,typically in the range of one-half to 2 mhz, with l mhz 'being used inthe embodiment disclosed herein. Clock pulses are connected by a gate 21to an output line 22. The gate 21 is a conventional circuit which isturned on to the open or transmit condition by each volume pulse on line23 and is turned off to the blocking condition by a stop pulse on line24. The clock pulse output from the gate is connected as an input to asale accumulator and as an input to a price counter. The saleaccumulator includes a first counter comprising three decade counterunits 30, 31, 32, connected to a second counter comprising three moredecade counter units 33, 34, 35, by a halfcent decode circuit, with theoutputs of the second counter decades feeding three display elements inan amount-of-sale display 36.

The price counter has three binary coded digital decade counter units40, 41, 42 connected in cascade with the clock pulses as an input. Thebinary coded output of each decade is converted to a decimal output in adecoder 43 and the 10 output lines of the decoders are connected to 10inputs of selector switches 44, 45, 46. Various conventional selectorswitches may be utilized and'the drawing illustrates a conventionalwafer switch having 10 input terminals and an output terminal '47 withthe output terminal making continuous contact on a rotating conductor 48and with a tongue 49 of the ring 48 engaging one of the 10 inputterminals.

The selector switches 44, 45, 46 are set to the price of the materialdispensed, typically a figure such as 37.9, representing the cost of thefuel in cents per gallon, with the switch 44 setting the leastsignificant figure or tenths of a cent, the switch 45 setting the unitsand the switch 46 setting the tens. A price display 50 may include threedisplay elements for displaying the price set by the switches 44, 45,46, with each switch having a second deck 44', 45, 46', respectively,for providing the signal for actuating the display element.

The output terminals 47 of the three selector switches are connected tothe stop count logic circuit for producing the stop signal on the line24 when the price counter has counted to the particular figure set bythe three selector switches. The stop count logic may utilize acoincident gate of some type and the preferred embodiment has two of theswitch outputs connected as inputs to a nor gate 52 and the'third switchoutput connected as the input to another nor gate 53, with the outputsof the two nor gates connected as inputs to a' nand gate 54.Alternatively, the set price could be binary coded and compared directlywith the count state of the units 40, 41, 42, to provide the stop signalwhen there is coincidence between the state of the three decades and thebinary coded set price.

When the gate 21 is switched to the on condition by a volume pulse online 23, clock pulses are transmitted to the price counter and arecounted in the decades 40, 41, 42. The gate 21 remains open until theprice counter reaches a count state corresponding to the setting of theswitches 44, 45, 46. At this time, there are outputs on each of thethreeoutput terminals 47, which outputs produce the stop signal on line24 through the stop count logic circuit. The gate 21 is switched to theoff condition and awaits another volume pulse on line 23. The nextvolume pulse resets the decades of the price counter to the initialcondition via line 23' and again switches the gate to the opencondition. The price counter again counts to the preset price figure andcloses the gate: This cycle is repeated for each volume pulse from thepulse generator.

When the gate is in the on or open condition, the pulse train sent tothe price counter is also sent to the sale accumulator, where it iscounted in the cascaded decades 3035.'We will first consider theoperation of the sale accumulator with the half-cent decode circuitomitted and with the decade 32 connected to the decade 33 in the normalmanner. With this arrangement and for sales in dollars and cents, eachclock pulse at the input of the decade 30 represents a sale of $0.0000lof material dispensed, and each pulse at the input of the decade 33represents $0.0] or 1 cent. With this arrangement, the calculation ofamount of sale and the display of the amount of sale would advance onecent at the completion of the metering of the entire one cents worth.However in many merchandising arrangements, it is desired to have the 1cent advance occur at the half-cent of dispensing time. That is, theamount of sale will change from zero to 1 cent when one-half cent ofmaterial has been dispensed and similarly, will change from 1 cent to 2cents when l xcents of material has been dispensed.

in the preferred embodiment of the present invention, the half-centdecode circuit between decades 32 and 33 provides this mode ofoperation. The half-cent decode circuit provides for passing a pulsefrom decade 32 to decade 33 with the fifth input pulse of decade 32rather than with the th input pulse, the latter being the normal mode ofoperating the decades in cascade. This is accomplished by utilizing alogic circuit which responds only to the fifth count state of the decade32. With a l-2-a-8 binary coded digital counter, the l, 2 and 4 outputsare connected in a coincident circuit, as by connecting the l and 4outputs as inputs to a nand gate 60 and connecting the 2 output to theinputs of another nand gate 61, with the output of gate 61 connected asthe third input to the gate 60. The gate 61 is operated as an inverter,and a nand gate is used for convenience because the gates 60, 61 come ina single package.

A reset circuit 65 provides a reset signal for the decades of the volumeand sale accumulators. Typically this may be a switch 66 which normallyconnects a voltage of a battery or other source 67 to the reset terminal(not shown) of each decade. Actuation of the switch 66 to connect theswitch output line 68 to circuit ground provides the reset operation.The

switch 66 may be actuated by the reset lever which is found onconventional gasoline pumps or a separate lever for actuating the switchmay be provided if desired. Another set of volume and sale accumulators,which are not reset by the reset circuit, may be provided to give atotal of sales for each day or other period as desired.

The calculator provides for continuous measurement, computation anddisplay of the volume of material dispensed and of the amount of sale.The volume and the amount of sale as calculated and displayed are inagreement at all times. As indicated above, the flow meter may operate arelatively low rate, typically producing pulses per gallon or about 25pulses per second, while the clock generator and the associatedcircuitry operate at a rate several orders of magnitude higher,typically in the range of one-half to 2 mhz. With a pulse generator rateof 100 pulses per gallon, the maximum rotational error due to the flowmeter will be less than one one-hundredth of a gallon per transaction,and will be independent of the amount of material dispensed pertransaction.

The outputs of the volume accumulator and the sale accumulator and thesetting of the selector switches are displayed digitally, for operationof the gasoline pump in the same manner as the conventional pumps.However it will be recognized that the electrical outputs from theaccumulators and switches may be used as inputs for computers andvarious data processing operations as well as for visual display. Also,each of the selector switches may be utilized to provide price settingfor a plurality of dispensers, typically all of the pumps at a station,as by providingan additional deck on the wafer switch for eachcalculator. Further, the price setting controls and the displays may beremote from each other and from the dispenser. 1

We claim:

1. In a calculator for a material dispenser, the combination of: t I

a volume pulse generator producing volume pulses as a function ofmaterial dispensed;

a clock pulse generator producing clock pulses;

a sale accumulator including means for counting input pulses anddisplaying the count state for indicating the monetary amount of a saleof material;

a price counter including means for counting input pulses;

means for developing a stop signal when said price counter counts to apredetermined figure and including means for changing said figure;

a gate circuit for passing pulses from the gate input to the gate outputwhen the gate is in the on condition and blocking pulses when the gateis in the off condition;

- means connecting said clock pulses to said gate input;

means connecting said gate output to the input of said sale accumulatorand to the input of said price counter;

means connecting said volume pulses to said gate circuit in controllingrelation for switching the gate circuit to the on condition for eachvolume pulse;

means connecting said volume pulses to said gate circuit in controllingrelation for switching the gate circuit to the off condition; and vmeans for resetting said price counter to the initial count state foreach volume pulse;

with said sale accumulator counting for each volume pulse, a number ofclock pulses corresponding to the price of a unit volume of material.

2. A calculator as defined in claim 1 in which said volume pulsegenerator operates at a relatively low pulse rate and said clock pulsegenerator operates at a relatively high pulse rate at least severalorders of magnitude greater than said low pulse rate.

3. A calculator as defined in claim 1 including a volume accumulatorhaving means for counting input pulses and displaying the count statefor indicating the volume of material dispensed, and

means connecting said volume pulses to the input of said volumeaccumulator.

4. A calculator as defined in claim 3 including price means fordisplaying said predetermined figure, and

means connecting said means for developing a stop signal to said pricemeans for changing the displaying thereof when said figure is changed.

5. A calculator as defined in claim 4 including a reset circuit having aswitch for actuation by the party dispensing the material, and

means connecting said reset circuit to said sale and volume accumulatorsfor resetting them to the initial condition when said switch isactuated.

6. A calculator as defined in claim 5 in which said volume pulsegenerator includes a meter driving a shaft rotating as a function offlow, and a switch actuated by said rotating shaft.

7. A calculator as defined in claim 1 in which said sale accumulatorincludes:

a first counter having clock pulses as an input and counting to aunit-of-sale corresponding to the smallest monetary value calculated anddisplayed;

a second counter providing an output for each of said unitsof-sale anddecimal multiples thereof; and

a half unit-of-sale decoder connecting said first counter to said secondcounter, said decoder transmitting a pulse from said first counter tosaid second counter when said decoder means for converting the countstate of said price counter to a decimal code providing a multi digitdecimal output;

a selector switch for each digit of the predetermined figure and having10 inputs and an output;

means connecting each decoder means decimal output to a selector switchas inputs; and g a logic gate having each of said selector switchoutputs as an input and providing the stop signal when the count stateof said price counter corresponds to the setting of said selectorswitches.

50 UNITED STATES PATENT QFFICE v fiERHFICATE OF CQRRECTWN 3,666 928Dated Ma 30 1972 In n William F. Burke David A. Gihring and Thomas E. YJones It is certified that error appears in the abovef-identified patentand that said Letters Patent are hereby corrected as shown below:

Column 1:

Line 46, after flow", insert --meter are counted directly to provide anindication of volume--; Line 50, after "10th", insert a Line 68, delete"the" [first occurrence] before "amount of sale" Column 2:

Line 72, after "conductor", insert --ring- Column 3: v v 7 Line 63,"1-2-8043" should be --l-2-4'-8-- Column 4: Q

Line 57 "volume pulses" should be --stop signal" Signed and sealed this19th day of December 1972. v

Attest:

EDWARD MFLETCHER,JR. ROBERT GOTISCHALK Attes'ting Officer 1 Commissionerof Patents- L I x J.

' UNlTED STATES PATENT GFFICE CERTIFICATE UF CORECTFN Pate n NO- 3 666928 v Dated May 36 g 1972 n )William F. Burke, David A. Gihring andThomas E. 1 Jones It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

' '1 Column 1:

Line 46, after "flow", insert --meter are counted directly to provide anindication of volume--; Line 5G after "10th", insert Line 68, delete"the" [first occurrence] before "amount of sale" Y Column 2:

Line 72, after "conductor", insert --ring-- Column 3:

Line 63, "l-2a'-8" should be --l-2-4-8-- I Column 4:

Line 57, "volume pulses" should be "stop signal-- Signed and sealed this19th day of December 1972.

(SEAL) Attesc: V

EDWARD M.FIETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents-

1. In a calculator for a material dispenser, the combination of: avolume pulse generator producing volume pulses as a function of materialdispensed; a clock pulse generator producing clock pulses; a saleaccumulator including means for counting input pulses and displaying thecount state for indicating the monetary amount of a sale of material; aprice counter including means for counting input pulses; means fordeveloping a stop signal when said price counter counts to apredetermined figure and including means for changing said figure; agate circuit for passing pulses from the gate input to the gate outputwhen the gate is in the on condition and blocking pulses when the gateis in the off condition; means connecting said clock pulses to said gateinput; means connecting said gate output to the input of said saleaccumulator and to the input of said price counter; means connectingsaid volume pulses to said gate circuit in controlling relation forswitching the gate circuit to the on condition for each volume pulse;means connecting said volume pulses to said gate circuit in controllingrelation for switching the gate circuit to the off condition; and meansfor resetting said price counter to the initial count state for eachvolume pulse; with said sale accumulator counting for each volume pulse,a number of clock pulses corresponding to the price of a unit volume ofmaterial.
 2. A calculator as defined in claim 1 in which said volumepulse generator operates at a relatively low pulse rate and said clockpulse generator operates at a relatively high pulse rate at leastseveral orders of magnitude greater than said low pulse rate.
 3. Acalculator as defined in claim 1 including a volume accumulator havingmeans for counting input pulses and displaying the count state forindicating the volume of material dispensed, and means connecting saidvolume pulses to the input of said volume accumulator.
 4. A calculatoras defined in claim 3 including price means for displaying saidpredetermined figure, and means connecting said means for developing astop signal to said price means for changing the displaying thereof whensaid figure is changed.
 5. A calculator as defined in claim 4 includinga reset circuit having a switch for actuation by the party dispensingthe material, and means connecting said reset circuit to said sale andvolume accumulators for resetting them to the initial condition whensaid switch is actuated.
 6. A calculator as defined in claim 5 in whichsaid volume pulse generator includes a meter driving a shaft rotating asa function of flow, and a switch actuated by said rotating shaft.
 7. Acalculator as defined in claim 1 in which said sale accumulatorincludes: a first counter having clock pulses as an input and countingto a unit-of-sale corresponding to the smallest monetary valuecalculated and displayed; a second counter providing an output for eachof said units-of-sale and decimal multiples thereof; and a halfunit-of-sale decoder connecting said first counter to said secondcounter, said decoder transmitting a pulse from said first counter tosaid second counter when said first counter has counted to one-half of aunit-of-sale.
 8. A calculator as defined in claim 7 in which said firstcounter includes a decade counter unit counting in 10ths of saidunit-of-sale and having an output for each 10th counted, and saiddecoder includes a logic gate having at least some of said counter unitoutputs as inputs and providing an output to said second counter onlyfor the five-tenths count state.
 9. A calculator as defined in claim 1in which said means for developing a stop signal includes: decoder meansfor converting the count state of said price counter to a decimal codeproviding a mUlti digit decimal output; a selector switch for each digitof the predetermined figure and having 10 inputs and an output; meansconnecting each decoder means decimal output to a selector switch asinputs; and a logic gate having each of said selector switch outputs asan input and providing the stop signal when the count state of saidprice counter corresponds to the setting of said selector switches.